1. Field of the Invention
The invention relates to a technology for audio input interface, and more particularly to an expandable device for wireless audio input.
2. Related Art
With the progress of the technology, the electronic technology has been progressed from the earliest vacuum tube and transistor to the integrated circuit chip, which has the quite wide applications. Thus, the electronic products have gradually become the indispensable essentials in the life of the modern human beings. At present, electrical product, such as DVD player, audio amplifier, and so on, has functions of audio output and audio play. In addition, some electrical product also has function for playing the inputted external audio signal, that is, the speaker of the electrical product is adopted for producing sound in response to the external audio signal input.
Electrical product with function for playing the external audio signal may include an audio process module, a control module, an audio amplifier, an audio I/O module and an audio playback device. When playing the music is required, the control module is operated to generate a control signal. The audio process module responds the control signal to decode the audio file to output a decoded audio signal, and the audio amplifier amplifies the decoded audio signal to output a driving signal adapted for driving the audio playback device, such that the audio playback device plays the music carrier by the decoded audio signal. The audio I/O module couples to the audio process module and the audio amplifier for outputting audio signal outputted from the audio process module.
When a user wants to play the external audio signal input through the electrical product, the audio I/O module can receives the external audio signal input and transmits the external audio signal input to the audio amplifier to amplify the external audio signal input to obtain the driving signal for driving the audio playback device. However, the number of the external audio jack of the electrical product is limited, and one external audio jack can only receive one external audio signal input from the external device. When pluralities of external audio signal inputs is required to be inputted in the electrical product, the first issue that the user meets is the lack of the audio jack.